1. Field of the Invention
The present invention relates to a sewing machine of the type comprising a bed defining a workpiece supporting table along which a workpiece is caused to move; a presser foot acting upon the workpiece to push it towards the supporting table; sewing means acting through the supporting table in the region of said presser foot in order to sew the workpiece; feed means to feed the presser foot with at least a ribbon-like piece of trimmings during the execution of stitching; an engagement seat formed in a front portion of the presser foot and arranged to guide the piece of trimmings under the presser foot through a slit extending transversely to the shoe; and cutting means to cut the piece of trimmings upstream of the presser foot.
The sewing machine of the invention is particularly adapted to be used when garments consisting of several component parts to be assembled together and to which it may be necessary to add elastic bands, support tapes and the like of different widths, have to be manufactured.
2. Prior Art
It is known that there are sewing machines capable of joining elastic bands, tapes or other types of trimmings to a workpiece as the latter is being sewn.
To this end these sewing machines are comprised of a presser foot which is provided, at the front portion thereof, with an engagement seat terminating in a slit extending transversely to the presser foot shoe, in front of a central portion of the presser foot itself. The ribbon-like trimmings to be engaged with the stitching are first wound to form a roll and during the stitching are submitted to the action of feed means which gradually unwinds them and sends them to the engagement seat. So the piece of trimmings engages in the seat and is thereby guided under the central portion of the presser foot, in which region the stitching takes place.
Provision is also made for a cutting unit fastened to the sewing machine bed so as to be disposed before the presser foot in a raised position with respect to the same. The cutting unit acts upon the piece of trimmings moving towards the presser foot in order to cut it at the appropriate time.
Sewing machines of the above type have some drawbacks as regards their practicality in use and versatility. In greater detail, it is to be noted that the fixed positioning of the cutting unit in front of the machine presser foot often hinders the movements performed by an operator when he is handling a workpiece. For the above reason it is better to resort to the sewing machines of the type in reference exclusively when trimmings have to be applied during the stitching, whereas conventional sewing machines devoid of said feed means and cutting unit are used when normal stitchings are concerned, that is when there is no need to add trimmings. Furthermore, in the machines of the known art the engagement seat in the presser foot has a substantially fixed width so that it is hardly adapted to apply trimmings having different widths. In other words, it is impossible to use the same presser foot to sew trimmings, for example elastic bands, to the waist and sleeves of garments which necessarily have different widths.
On the contrary, when the width of a piece of trimmings to be applied is different from that of the trimmings applied before, the presser foot must be replaced or another machine suitably arranged with an appropriate presser foot must be used.
In conclusion, at the present state of the art it is always necessary to use two or more sewing machines when a workpiece consisting of several parts and provided with ribbon-like trimmings must be manufactured.